Industrial Ventilation Rates

[Engineer6512]

I am designing the HVAC systems for an industrial pumphouse, and am trying to determine what to use as an OA ventilation rate.

The building is normally unoccupied, and there are no out of the ordinary sources of contaminants. The building houses a number of pumps - I need about 600 cfm of OA during the summer for heat dissipation. What I would like to do though is ensure that this 600 cfm is adequate to meet ASHRAE standards for air quality. Unfortunately I haven't found anything in Standard 62 or the Applications & Fundamentals books to provide a standard ventilation rate for this type of situation.

Is there a standard ventilation rate for industrial facilities that is not based on heat dissipation or contaminent dilution?

 

[walkes]

There may be some guidance in NFPA, certain facilities such as water treatment and sewage treatment plants have a required airflow for dissipating gases like H2S. Some guidelines seem to use 1 CFM/sq ft for a ventilation rate for some industrial spaces, others may use an air change rate for the space.

 

[Engineer6512]

Thanks for the reply. That's what I'm getting at though... what is an acceptable Air Change per hour rate for industrial / process buildings that have negligible heat and/or contaminent generation and are usually unoccupied?

If I look in "ASHRAE Applications", under 'power plants' for example, all of the approximate ACH rates are given assuming heat dissipation.

 

[Welchita]

Pumhouse means as well internal heat sources. This can be related with with your question and to impose some ventilation rate, as well !?
welch

 

[Welchita]

What i mean, unless we dealing with a very contaminated environment, the necessary and higher ventilations rates are usully obtained based on the criterious concerning internal heat sources.
Welch

 

[Engineer6512]

Yes I recognize that - thanks for the reply, but as I stated in my post, this particular building has negligible internal heat gain. It has only a few small pumps in one corner, and the rest is all piping (cold water).

Another building I am doing is an electrical house that has its cooling through DX air conditioning to handle the heat load. The building will still require some fresh air ventilation however... what should I use for a rate? The ASHRAE std 62 rate for a computer room?

 

[trashcanman]

Treat it like a toilet, 2 CFM/Sq.Ft.

 

[Welchita]

Whar Trashcanman declares sounds logical: - the rate he refers, means 10 to 12 times the volume of related space. Or, the air is replaced every 5 to 6 minutes.

 

[fcxdfm]

Pump Room: Use 1-2 cfm/ sq ft, or cfm required for temperature control of the space, use whichever is bigger. It looks you don't need ventilation in the winter for energy saving purpose.

MCC Room: If the room is unoccupied, use 100% return. No need for outside air.